Field of the Invention
The invention relates to a circuit configuration having single-electron components and which is suitable, inter alia, for use as a logic circuit.
At the present time, integrated circuit configurations for logic applications generally use CMOS technology. As components progressively become smaller, this conventional CMOS technology is reaching its limits.
With regard to further miniaturization, so-called single-electron components have been proposed, in which switching processes are carried out using individual electrons. An investigation into such single-electron components is known, for example, from W. Rosner et al, Microelectronic Engineering, Volume 27, 1995, pages 55 to 58. Single-electron components are tunnel elements that are connected to adjacent connections via tunnel contacts. Charge movements through these tunnel contacts take place both by means of the quantum-mechanics tunnel effect and simply by thermally overcoming a potential barrier, in which these charge movements occur sufficiently rarely. The tunnel elements are, for example, in the form of small conductive islands that are surrounded by an insulating structure. If a voltage U that satisfies the condition for Coulomb blockade is applied to the two connections, that is to say whose magnitude is: EQU .vertline.U.vertline.&lt;e/(2C)
then the charge of the tunnel element cannot change, because of the potential conditions, provided, for the thermal energy: ##EQU1##
In this case, k is the Stefan Boltzmann constant, T is the temperature, e is the electron charge, and C is the capacitance of the tunnel element.
If a greater voltage is applied, electrons can flow via one of the tunnel contacts to the tunnel element. These single-electron components are operated such that individual electrons move in each case.
By actuating the tunnel element via a gate electrode which capacitively influences the tunnel element without any tunnel movements occurring in the operating voltage range, it is possible to overcome the Coulomb blockade. If the electrical charge acting at the gate electrode is suitable, the single-electron component has an approximately linear current/voltage characteristic that passes through the origin. Such a gate-controlled single-electron component is referred to as a single-electron transistor in the literature.